[RPG] How to integrate an implement based ranged basic attack with the Hunter’s Rapid Shot feature

Beyond the points that Acedrummer_CLB exquisitely exposed, I think that in every occasion you could apply more than one effect under the same conditions and these effects come from different sources (powers, feats, whatever), you could apply them in the order you prefer.

I have found no reference to support this "rule": I simply decided that if there is no explicit ordering criterion, an arbitrary one could be used.

I think, however, that the effects of all four feats in the example should fall under the hit or miss phase (they all apply only on a successful hit only).

Under this hypothesis while the decision to exploit the Deft Hurler option takes place before the attack, its effects, Cruel Cut Style, Longhand Student and Criterion of Balic Practice effects could all take place in the hit or miss phase.
These four effect are not simultaneous, but could be applied in any order. A possible sequence of play could be:

1. Before the attack: Deciding to use Deft Hurler
2. As you attack: You compute attack and damage bonus and check if you hit you primary target.
3. Hit or miss: You hit the Cleave target and deal damage as normal.
   1. You use the Longhand Student benefit, thus pushing the target one square (and isolating it from its allies).
   2. You use the Cruel Cut Style benefit to the now isolated target and deal it ongong Wisdom modifier damage.
   3. You use the Criterion of Balic Practice benefit and shift 1 (or 2) square(s); you are now in range for a ranged basic attack against the artillery monster.
   4. You use the Deft Hurler benefit to make a ranged basic attack against the artillery monster.
4. After the attack: none.

I have found no reference to rules that prohibit the appliance of multiple "at-will attack modifier" effects. A more formal at-will attack modifier definition or keyword may be needed.
However, as the number of publish material grows, some at-will attacks could become far more powerful than many encouter attacks.
I'd house rule that no more than one "at-will attack modifier" feat could be applied on a single power utilization; and this decision must be made in the before the attack phase.